Transcript Animals are Sweet!

Introduction to Animals
Essential Questions:
What makes an animal an animal?
How are animals classified?
What is an invertebrate versus a vertebrate?
What are the various classes of invertebrates
and vertebrates?
Kingdom Animalia
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Eukaryotic
Multicellular
Heterotrophic
Evolved ways of moving
to feed, reproduce, and
protect themselves
Specialized cells that
form tissues and organs
like nerves and muscles
Cells do not have cell
walls
Likely evolved from
animal-like protists
during the Cambrian
period.
Essential Functions
All animals carry out the following:
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Feeding: obtain food from the environment
Respiration: exchange O2 and CO2
Circulation: move materials around body
Excretion: get rid of wastes
Respond: process information with nerves
Move: all animals are motile at some point
Reproduce: most sexually, some asexually
What is coelom?
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Coelom – fluid filled cavity
that supports internal organs.
Acoelomates – have no
internal cavity.
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Pseudocoelomates – a
body cavity develops
between endoderm and
mesoderm.
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Why the Coelom?
The coelom is significant because
as animals evolved, so did the
presence of a complex body
cavity to support more complex
organs!
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Example: Flatworms
Example: Roundworms
Coelomates – internal
organs suspended in a body
cavity surrounded by
mesoderm.
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Example: Humans & Insects
Reproduction & Development
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Animals mainly reproduce sexually
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External fertilization (in water)
Internal fertilization (on land)
Steps of Development:
Most animals develop from a single
fertilized egg (zygote)
Fertilization – sperm meets egg, either
within or outside the body
The Unicellular zygote divides by mitosis
= cleavage
A hollow ball of cells forms a blastula (fluid
filled ball of cells.)
Gastrulation (folding inward) occurs to
form 2 cells layers: ectoderm and
endoderm
Mesoderm forms which will form the
muscles, circulatory system, excretory
system and respiratory system
Symmetry
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Animals can be described in
terms of their symmetry.
 Asymmetry – irregular in
shape
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Radial Symmetry – can be
divided through along any
plane into halves from the
mouth.
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Example: Sponge only!
Example: Hydra
Bilateral Symmetry – can
be divided lengthwise into 2
mirror images.
 Cephalization:
concentration of sense
organs at the front (top) of
the body
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Example: Humans
Body Plans
Body Positioning
Bisymmetrical animals have 4 parts:
 Anterior: the head end, where
sensory organs are located
 Posterior: the tail end (anus)
 Dorsal: Back surface where the
spine is located
 Ventral: The belly side
Other:
 Transverse: Cross section
straight through.
Framework for support: Skeletons
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To survive on land, it is important to
have a strong skeleton. WHY?
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Exoskeletons – hard, waxy
covering on the exterior of the
body.
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Prevent water loss, protect
soft tissues
Endoskeletons – internal
skeleton for support made of
Calcium Carbonate (starfish),
cartilage (sharks) or bone
(humans)
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Protects internal organs and
an internal brace for muscles
to pull against
Invertebrates – an animal
without a backbone; usually has
exoskeleton
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Echinoderms have
endoskeletons
Vertebrates – an animal with a
backbone; bilaterally symmetry;
exoskeleton
Types of Skeletons
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There are 3 types of
Skeletons
1. Hydrostatic
2. Endoskeleton
3. Exoskeleton
Vertebrate skeletons are
made of cartilage and/or
bone
Exoskeletons provide more
protection, however
endoskeletons provide
greater movement and
freer growth. Why?
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Exoskeletons must be molted
in order for the organism to
grow, leaving it open to
damage!
Invertebrates
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Make up 95% of all animals
 Have no backbone, or vertebral
column, mostly have
exoskeletons.
 Ruled the Earth during the early
Paleozoic Era/Cambrian Period
(540-500 mya)
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Called the “Age of Invertebrates”
Open circulatory systems (with a
one chambered “heart”)
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Cannot process Oxygen very well, restricts
their size and survival on land.
Invertebrate Phyla
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Phylum Porifera - Sponges
Phylum Cnidaria – Corals,
Hydra & Jellyfish
 Phylum Platyhelminthes Flatworms
 Phylum Nematoda –
Roundworms
 Phylum Mollusca – Snails, squid
& Clams
 Phylum Annelida - Segmented
Worms
 Phylum Arthropoda – Insects,
spiders, lobsters
 Phylum Enchinodermata –
Starfish
 Invertebrate chordates – Sea
squirts, Lancelets
Your Turn!
What is a Vertebrate?
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A vertebrate is an animal with a backbone
 Classification: Kingdom – Animalia / Phylum –
Chordata / Subphylum - Vertebrata
 Characteristics
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Have an endoskeleton
The backbone gives support to the body and
protection to the spinal cord
Cephalization = means the sensory organs and well
developed brain located in a skull
Closed circulatory system w/a multichambered
heart
Vertebrates: Am I hot or not?
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The major difference between
vertebrates is whether or not
they can regulate their own body
temperature.
Ectotherms – regulated by
environment
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Example: fish, frogs, snakes
Endotherms – regulated by their
own body
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Example: mammals, humans
Animals that are ectothermic (like snakes) don’t require food as much as endotherms.
• What does this mean in terms of food requirements and the generation of
body heat?
• How does this fact restrict where certain types of animals can live?
• If the environment were to suddenly get cold (like an ice age), which of the
animals could survive?
The Human Vertebrate
Skeleton
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There are 206 bones in
the human body
 Muscles aid in skeletal
movement. There are 100
joints in the human body
and 639 different muscles.
 Muscles and bones attach
by tendons and ligaments
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Tendons: Muscle to Bone
Ligaments: Bone to Bone
Bones…
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make blood,
store minerals,
protect internal organs
and allow movement
Axial versus Appendicular
Skeleton
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There are two sections to the
vertebrate skeleton:
1) Axial skeleton that includes the skull,
vertebral column, and rib cage.
Protects internal organs!
2) Appendicular Skeleton that includes
the arm, leg bones, pelvis and
shoulder.
Allows for Locomotion!
Movement: Joints
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There are four major Joints
in the skeleton
1) Ball and Socket – allows
for a wide range of motion
(shoulder, hip)
2) Hinge – back and forth
motion (elbow, knee)
3) Pivot – bones rotate
around one another (base of
skull)
4) Saddle/Gliding – bones
slide over one another (wrist,
ankle)
Vertebrate Phyla
– jawless fish, cartilage fish, bony fish
 Amphibians – Frogs
 Reptiles – Snakes, Turtles
 Avians – all Birds
 Mammals – have mammary glands and
hair/fur
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placental mammals (95% of all mammals)
marsupials (pouched mammals)
monotremes (egg laying mammals)
Vertebrate Phyla Chart
Your Turn!
Vertebrates - Fish
Fish are well adapted to water. (Evolved first in Earth’s
massive oceans)
 Ruled the Earth During the Devonian Period. (408 – 360 mya)
“Age of Fishes”
 Respire through Gills. Water rushes into the mouth, flaps
called opercula open and water is forced over the gills where
Oxygen is absorbed and Carbon Dioxide is released
 Closed, Single loop circulatory system with a 2 chambered
heart
 Have a swim bladder for buoyancy (won’t sink)
 Scales for protection and insulation
 Reproduce Sexually and typically Externally.
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There are distinct sexes with fish, although fertilization maybe internal or
external but always have many offspring, why?
Lots of offspring = little to no parental involvement.
• Exception to the Rule: Male Seahorses
3 Types of Fish
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Agnathans – Jawless
Fish. The most primitive
fish, like lamprey.
Chondrichthyes –
Cartilage Fish. (That’s
what their skeleton is made
up from, instead of bone.)
Adapted to deep sea life,
like sharks
Osteichthyes – Bony Fish.
Adapted to live in shallow
ocean and freshwater.
Class Amphibia
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Characteristics
external fertilization (must happen in water)
Double loop closed circulatory system with a Three
chambered heart
Breathes via primitive lungs and through their moist skin
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Highly dependent on a source of water for surivival.
ectothermal – body temperature changes with
surroundings
metamorphisis – aquatic larva  semi-terrestrial adults
Ruled the earth during the Permian Period (280-248
mya) “Age of Amphibians”
Three Orders
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Caudata: salamanders and newts
Anura: frogs and toads
Apoda: legless caecilians
Class Reptilia
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Ruled the Earth during the Mesozoic Era (248-65
mya) Called the “Age of Reptiles.”
scaly skin and respire via Lungs only.
reproduce internally.
• on land and lay amniotic eggs
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ectothermal
Closed loop with 3-chambered heart
• (except crocs and alligators, have a 4 chambered heart)
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Some or no parental involvement in raising
offspring. (Crocs yes, snakes no)
 Orders:
Squamata, Crocodilia, Testudines
Your Turn!
Class Aves
Characteristics:
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Feathers and possibly wings (may or may not fly)
Wings, scaly legs
Highly Oxygen efficient 4 chambered heart,
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Flying birds: 1 way respiratory system for constant
intake of oxygen
Hollow and fused bones to remain light for flight
Endothermic – maintain a constant body
temperature (can live anywhere on Earth)
Internal fertilization and lay amniotic eggs
Fewer offspring and a High level of parental
involvement in raising offspring.
Class Mammalia
Characteristics:
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Hair or Fur
Rules the Earth in the Cenozoic Era (65 mya to today)
Called the “Age of Mammals.”
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nurse young – have mammary glands
Endothermal – can live anywhere on Earth
Highly Oxygen efficient 4-chambered heart
Respire though lungs only (including whales)
different types of teeth adapted to their unique diet.
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Quaternary Period (1.8 mya to today) called "The Age of Man"
Sharp canines – Carnivores
Flat molars – Herbivores
Mixed canines & molars - Omnivores
Few offspring and High level of parental involvement in
raising offspring
Types of Mammals
– based on type of
reproduction
 Subclasses
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Placental (95%) – young fully develops in
uterus before birth
Marsupials – short period of development
inside the moth followed by a second period
of development inside pouch
Monotremes (3 species) – lay eggs, platypus
and 2 echidnas
Your Turn!